Rolls driving gear for the stand of pipe cold-rolling mill

ABSTRACT

A driving gear of rolls has cranks set on the roll necks, a slide block traveling parallel to the rolling axis in guides secured on the roll housing, and connecting rods hinged to the cranks and the slide block. The slide block moves, under the action of a cam mechanism, in rolling with a speed permitting to equalize the peripheral speed of the rolls rotation and the rate of the metal creep within the deformation source during rolling.

States Patent Kozhevnikov et al.

{111 3,842,636 Oct. 22, 1974 ROLLS DRIVING GEAR FOR THE STAND OF PIPE COLD-ROLLING MILL [76] Inventors: Sergei Nikoiaevich Kozhevnikov, ulitsa Vystavochnaya, 3, kv. 73, Kiev; Arkady Semenovich Tkachenko, prospekt Gegarina, 63, kv. 22; [got Vasilievich Murash, ulitsa Moskovskaya, l4, kv. 108, both of Dnepropetrovsk; Anton Antonovich Shvedchenko, ulitsa Pestelya, 4, kv. l, Nikopol, all of U.S.S.R.

[22] Filed: Nov. 21, 1973 [21] Appl. No.: 418,076

[52] U.S. Cl 72/208, 72/220, 72/249 [5]] Int. Cl ..B21b 17/10 [58] Field of Search 72/208, 209, 214, 220,

[56] References Cited UNITED STATES PATENTS 2,780,948 2/l957 Fredricksson 72/189 3,570,294 3/197] Shibuta.; 72/208 Primary Examiner-Milton S. Mehr Attorney, Agent, or Firm-Waters, Roditi, Schwartz & Nissen 5 7 ABSTRACT A driving gear of rolls has cranks set on the roll necks, a slide block traveling parallel to the rolling axis in guides secured on the roll housing, and connecting rods hinged to the cranks and the slide block. The slide block moves, under the action of a cam mechanism, in rolling with a speed permitting to equalize the peripheral speed of the rolls rotation and the rate of the metal creep within the deformation source during rolling.

1 Claim, 4 Drawing Figures ROLLS DRIVING GEAR FOR THE STAND OF PIPE COLD-ROLLING MILL The present invention relates to mechanisms for pipe cold-rolling mills and more particularly to rolls driving gears for the stands of pipe cold-rolling mills.

Known in the art is a driving gear of rolls for the stand of the pipe cold-rolling mill, comprising pinions set on necks of the rolls arranged in a mobile stand and tooth racks secured immovably on the housing of the mill. In the reciprocating motion of the stand, the pinions, while rolling on the rack secured on the mill housing, impart reciprocating rotation to said rolls.

With the provision of the above known driving gear of the rolls, the reciprocating rotation of these rolls is at a constant speed, which is a disadvantage, as the roll groove has a pass of a variable section and the rate of a metal creep in rolling is thus variable. At the same time, the production of quality pipes makes it imperative that the speed of the rolls rotation in rolling be equal to the rate of creep of the metal.

Another major disadvantage of this driving gear of the rolls is the presence of considerable dynamic loads developing in the drive parts due to the wear of the teeth or inaccuracy in setup.

Furthermore, this rolls driving gear is complicated in mounting, setting, adjustment, and operation.

Also known is a drive of the rolls of the pipe coldrolling mill, comprising a bar link one end of which is hinged to the crank set on the roll neck, the second one being hinged to the mill housing, and a rack secured on the stand so that it has a roller thereon fitting into the groove of the bar link with which it interacts.

During the reciprocating motion of the stand, forces develop in the bar link, that make the rolls turn and r tate reciprocatingly. In the middle position, when the bar link is passing the dead point, the roller becomes engaged and, a result of its interaction with the bar link, brings it out of that position.

It is not possible to make this drive with an angle of turn of more than 220C, which is a disadvantage, as horse-shoe-shaped and circular passes becoming common at present necessitate a larger angle of turn for the rolls.

The design of the driving gear of the rolls also fails to ensure completely required variations in the speed of the rolls rotation in the course of rolling, which impairs the quality of produced pipes.

An object of the present invention is to provide a driving gear of the rolls, simple in design and dependable in operation.

Another object of the invention is to provide a driving gear of the rolls, as would permit an angle of turn of up to 360 for said rolls.

Yet another object of the invention is to provide a driving gear of the rolls, as would help produce quality pipes.

The above and other objects of the invention are accomplished by providing a driving gear of the rolls of the stand of the pipe cold-rolling mill, comprising cranks set on the necks of the rolls and hinged to amechanism designed to transmit to said cranks forces that effect the turn of the rolls. According to the invention, the mechanism for transmitting to the cranks forces that effect the turn of the rolls is made as two crank and also hinged, with the other end each, to a slide block reciprocating parallel to the rolling axis in guides secured on the roll housing at a rate that helps equalize the speed of the rolls rotation and the rate of the metal creep in the deformation source during rollmg.

The present invention is realized as a driving gear of the rolls of the stand of the pipe cold-rolling mill, dependable in operation and simple in design, that permits to increase the angle of the rolls turn up to 360 as well as ensures a variable speed of the rolls rotation, equal to the rate of the metal creep in the source of deformation during rolling, which helps reduce the rolling force, improve the quality of pipes produced, increase the number of the double strokes of the mill stand per minute and raise the efficiency of the mill.

The invention will be more apparent from the description of its exemplary embodiment and related drawings, wherein:

FIG. 1 shows a functional diagram of the pipe coldrolling mill equipped with the rolls driving gear embodied according to the invention;

FIG. 2 shows a stand of the pipe cold-rolling mill embodied according to the invention, lateral view;

FIG. 3 is ditto, buttend view; and

FIG. 4 shows the diagram of positions of the rolls driving gear, with 13 different positions of the latter, each corresponding to one stand stroke.

On FlG.l showing a functional diagram of a pipe cold-rolling mill, rotation from an electromotor 1 is transmitted, via a main reducer 2, to a crank-andconnecting-rod mechanism 3 which imparts reciprocating motion to a working stand 4. One complete revolution of the crank-and-connecting rod mechanism 3 involves a double stroke of the working stand 4: a forward stroke in the direction (shown by arrow) of the escape of a ready pipe and a reverse stroke in an op posite direction.

The rotation of rolls 5 is carried out by means of a rolls driving gear 6 made according to the invention. From the main reducer 2, rotation is transmitted to the reducer 7 of a cam mechanism 8 and a traversing mechanism 9. In the extreme backward position of the working stand, there is a feed of a pipe 10, its turn being effected when said working stand is in its extreme forward position. A mechanism 11 serves for setting and withdrawing a rod 12 designed to fix a mandrel (not shown).

The rolls driving gear 6 has two connecting rods 13 (FIGS. 2 and 3) hinged, with one end each, to cranks 14 set on necks 15 of said rolls 5, and with the other ends also hinged to aslide block 16 travelling within guides 17 of a base 18 of the stand 4.

On the diagram of positions of the rolls driving gear at different positions of said rolls, that correspond to one stroke of the stand (FIG. 4), number I stands for a position of the rolls, that corresponds to the extreme forward position of the stand, II for the middle position of the stand, III for the extreme backward position of the stand, IV for the plane of displacement of the axis 0-,-0 of the upper roll 5, V for the plane of displacement of the axis 0 0 of the slide block 16, and VI for the plane of displacement of the axis 0 0 of the lower roll.

The rolls driving gear functions as follows.

During the reciprocating motion of the working stand 4 the slide block 16 is also imparted reciprocating dis placement. As the path covered by said slide block 16 in one stroke of the stand 4 is but a part of the path covered by said stand, as shown on FIG. 4, the rate of displacement of the slide block 16 is smaller than that of the stand 4, and therefore forces develop in the connecting rods 13, under the action of which the rolls 5 make a turn and start reciprocating rotation. Variations in the speed of rotation of said rolls 5 depend on variations in the speed of travelof the slide block 16.

The displacement of the slide block 16 can be effected e.g., with the aid of a cam mechanism 19 coupled with a main drive 20 of the stand via a reducer 21.

The cam profile should be such as to enable the lever 24, which interacts with the cam via the rollers 23, to impart the slide block 16, via the connecting rod 25, a motion at a speed corresponding to the rate of the metal creep within the deformation source in the course of rolling.

In case of the change-over to another standard of rolled pipes, the rate of the metal creep within the deformation source in rolling will be different due to a varied profile of the groove of the passes. Consequently, it is necessary to vary the speed of the rolls rotation and, naturally, that of the slide block 16. This is achieved by varying the arms of the lever 24 through displacing the swing support 26 relative to said lever 24. Variations in the arms of the lever 24 result in 21 varied length of travel of the slide block 16 and, consequently, a varied speed of rotation of the rolls 5.

What we claim is:

1. A driving gear of rolls of stand of a pipe coldrolling mill, comprising: cranks set on necks of said rolls; a mechanism for imparting reciprocating motion to said stand, kinematically coupled with the main drive of said mill; connecting rods hinged, with one end each, to said cranks, a slide block hinged to the other ends of said connecting rods and adjusted for reciprocating motion parallel to the rolling axis during the reciprocating travel of said stand; guides for the reciprocating motion of said slide block, secured on the housing of said stand; a device kinematically coupled with the main drive of said mill for moving said slide block at a speed permitting the turn of said rolls with a circumferential speed equal to the rate of metal creep within a deformation source during rolling. 

1. A driving gear of rolls of stand of a pipe cold-rolling mill, comprising: cranks set on necks of said rolls; a mechanism for imparting reciprocating motion to said stand, kinematically coupled with the main drive of said mill; connecting rods hinged, with one end each, to said cranks, a slide block hinged to the other ends of said connecting rods and adjusted for reciprocating motion parallel to the rolling axis during the reciprocating travel of said stand; guides for the reciprocating motion of said slide block, secured on the housing of said stand; a device kinematically coupled with the main drive of said mill for moving said slide block at a speed permitting the turn of said rolls with a circumferential speed equal to the rate of metal creep within a deformation source during rolling. 